MP2625B – SINGLE CELL SWITCHING CHARGER WITH POWER PATH CONTROL

MP2625B Rev. 1.01

www.MonolithicPower.com

17

1/15/2018

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Table 1: Input Current Limit Setting

M0

M1

Mode

Low

Low

USB2.0 Mode

Low

High

USB3.0 Mode

High

Low

Programmable Mode

High/Float High/Float Default Mode

Input Voltage Limit Setting

The input voltage can be limited at a value set by

a resistor divider from IN pin to VLIM pin to

AGND according to the following expression

(Typical Application Circuit):

IN_LIM

R1+R2

V

=1.52

(V)

R2



When the voltage on VLIM pin drops and hits the

reference voltage 1.52V, the input voltage will be

clamped to the setting value.

Battery Charger

The MP2625B completes charge operation

consist of trickle charge, automatic charge

termination, charge status indication, timer

control, NTC indication, automatic recharge, and

thermal limiting.

When the PWM converter is out of soft start, the

battery charge cycle begins, the MP2625B first

determines if the battery is deeply discharged. If

the battery voltage is lower than the trick charge

threshold (typical 3.0V), the battery charger starts

in “trickle charge mode”. The trickle charge

current is limited to 10% of the programmed

charge current until the battery voltage reaches

3.0V. If the charge stays in the “trickle charging

mode” for longer than “trickle charge timer

period”, the “timer out” condition is triggered, the

charge is terminated and CHGOK

_____________

will start

blinking

to

indicate

that

the

battery

is

unresponsive. When the battery voltage is above

3.0V, the charger is operating at “constant

current mode.” The current delivered to the

battery will try to reach the value programmed by

the ISET pin. Depending on the available input

power and system load conditions,

the battery charger may or may not be able to

charge at the full programmed rate. The system

load is always satisfied first over the battery

charge current. If the system load requirement is

low, the battery can be charged at full constant

current.

When the battery voltage reaches the battery full

threshold, the charger enters the “constant

voltage mode” operation.

End of Charge (EOC) and Indication

In constant voltage charge mode, the battery

voltage is regulated at 4.2V (when SYSFB is float

or SYS is programmed higher than battery full

threshold) and the charge current decreases

naturally. Once the charge current hits the

charge current), the battery is fully charged and

charge cycle is terminated.

any limit condition, the MP2625B will come out of

CV mode, and the charge full detection is invalid.

A safe timer starts at the beginning of each new

charge cycle and it monitors if the whole charge

period is within the programmed time limit. After

each charge cycle, when the battery is indicated

as full, the timer counter will be reset. If the time

is expired while the charging is still on going, the

timer will force the MP2625B to terminate

charging CHGOK

_____________

is blinking to indicate the fault

condition.

If system voltage is programmed lower than 4.2V

by the resistor divider at the SYSFB pin, the

Automatic Recharge

Once the battery charge cycle is completed, the

MP2625B turns off indicating the battery full

status. During this process, the battery power

may be consumed by the system load or self

discharge. If the input power is always on, to

ensure the battery not to be exhausted, the new

charge cycle will automatically begin when the

battery voltage falls below the auto-recharge

SYSFB is float, and 50mV lower if the SYSFB is

connected to a resistor divider. The timer will re-

start when the auto-recharge cycle begins.

During the charge off state when the battery is

fully charged, if the input power is recycled, or

the EN signal is refreshed, the charge cycle will

re-start and the timer will refresh even if the